For several years, automated “sort machines” have been available which sort large volumes of documents (e.g. letters, postcards, checks, flats, and the like) into groups having a common identifying criteria (e.g. Zip Codes, mail boxes, etc.). A sort machine is typically comprised a “front end” or feed section and one or more “stacker sections”. The front end feeds the pieces, one-by-one, past a reader (e.g. optical character reader (“OCR”), bar code reader (“BCR”), or the like) and onto a transport that carries it to a designated sort pocket in the stacker section(s).
As the piece passes the reader, the desired criteria on a piece is read and a signal is generated that, in turn, is processed to generate a designation signal for that particular piece. This designation signal, in turn, triggers a diverter or “gate” at the designated pocket in the stacker section as the piece approaches to divert the piece from the transport into the designated pocket where it is stacked with other pieces having the same identifying criteria. Such machines are well known and are commercially-available, e.g. Vsort™ Flat Sort Machine, OMEGA™ Sort Machine, both manufactured and distributed by National Presort, Inc., Dallas, Tex.
One problem that exists in such machines arises from the occasional jamming of pieces as they are diverted into their designated pockets. One major cause of this jamming is that the “tail” of a previously diverted piece is not sufficiently moved away from gate (i.e. pocket entry) and into the pocket so that it may interfere with the leading edge of the next piece diverted into that same pocket. That is, if the tail of the last piece in a particular pocket is not moved sufficiently into the pocket and away from the gate, the leading edge of the next piece can be driven into the tail of the last piece thereby causing a “jam”.
One highly successful “fix” in alleviating jamming in machines of this type is to provide a “kicker” at each pocket which aligns with the gate of that pocket when the gate is actuated to divert a piece into the pocket. This allows smooth entry of the piece from the transport into the pocket. Once the piece has cleared the pocket's entry, the kicker is moved to “kick” the tail of that piece inwardly into the pocket and away from the entry point into the pocket. This allows the next piece to smoothly enter the pocket without engaging the tail of the previous piece. For complete details of such an anti-jamming means, i.e. “kicker”, see U.S. Pat. Re. 34,330, which is incorporated herein in its entirety by reference.
While this kicker works extremely well in preventing jamming in most instances (even with a wide variety of different types of mail pieces), there are some instances where the possibility of jamming still exists. For example, if the pieces are too stiff (e.g. glossy brochures) or too flimsy (e.g. tissue paper-like pieces), the tails of these pieces may not stay in the “kicked” position but may have a tendency to return toward the entry of the pocket once the kicker returns to its original position. Hence, the tail of the last sorted piece will be exposed for possible contact with the next piece entering that pocket and jamming can occur. Since the commercial market for this type of sort machines is highly competitive, any improvement in preventing jams may be significant in selling the machines since the downtime required for clearing jams is a major consideration when selecting the machine.